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Record depletion of ozone over Arctic

Geneva, April 5, 2011

Record loss of the ozone, the atmosphere layer that shields life from the sun's harmful rays, has been observed over the Arctic in recent months, the World Meteorological Organization said on Tuesday.

"Depletion of the ozone...has reached an unprecedented level over the Arctic this spring because of the continuing presence of ozone-depleting substances in the atmosphere and a very cold winter in the stratosphere," the WMO said in a statement.

Observations from the ground, balloons and satellites show that the region has suffered an ozone column loss of about 40 percent from the beginning of the winter to late March, according to the United Nations agency.

The highest ozone loss previously recorded over the Arctic, about 30 percent, occured in several seasons over the past 15 years or so, according to a WMO spokeswoman.

"If the ozone depleted area moves away from the pole and towards lower latitudes one can expect increased ultraviolet (UV) radiation as compared to the normal for the season," WMO said, adding that the public should check their national UV forecasts.

But any increase in UV radiation over lower latitudes away from the Arctic -- which could affect parts of Canada, Nordic countries, Russia and Alaska in the United States -- would not be of the same intensity as one suffers in the tropics, it said.

UV-B rays have been linked to skin cancer, cataracts and damage to the human immune system. "Some crops and forms of marine life can also suffer adverse effects," the agency said.

Unlike over Antarctica, large ozone loss is not an annually recurring phenomenon in the Arctic stratosphere, where meteorological conditions vary much more each year.

The record ozone loss over the Arctic comes despite the "very successful" Montreal Protocol aimed at cutting production and consumption of ozone-destroying chemicals such as chlorofluorocarbons (CFCs) and halons, the WMO said.

The substances were once present in refrigerators, spray cans and fire extinguishers, but have been phased out. Nevertheless, due to the long lifetimes of these compounds in the atmosphere, it will take several decades before their concentrations return to pre-1980 levels, the target laid down in the 1987 pact, it said. - Reuters